So, devils advocate, yeah we know that the little brother is a really well written character who had an unchecked mental issue that grew up without a solid family dynamic (brother who pampers him and families that definitely didn't punish him the way he needed) making him seek out destructive behavior to try and get a punishment in return since he craves the solid love that comes from someone who's willing to tell you you're wrong. (Roughly) he should've ended up with someone who didnt push or bend at any turn and who didn't run in the face of bad behavior without punishment first. Think a more extreme brat tamer for a brat who's willing to actually abuse people. This isn't really devil's advocate, Ive decided to mentally show that a romantic ending was possible and then guess what the author was doing. I don't mind him ending with someone older, I think he might need someone closer to his age range because he seeing his partner as a paternal figure is very very iffy if done long term.
(We could fight the fact that he didnt call the professor mom/dad ALL the time and it was more used for either comfort or manipulation when used but I'd also fight that he viewed the professor as a paternal figure every second of their relationship with the punishment seeking behavior).
(Back onto devils advocate) I think the author was trying to show that healing isn't linear, and that especially with mentally ill partners, often times it's about riding out storms or more known metal health episodes (in this case it's the punishment seeking abuse) to get to what you appreciate about your partner, and that you can help your partner through tough times And be there without letting your partner not learn consequences (he would scold the little brother) and that you don't have to abuse your partner back for relationships like that to work But because the professor is so SO soft and lenient with the little brother it falls flat. Especially at the end. They should've had at least a serious conversation with boundaries (we've seen that the author can write that) and finally show that they're healing because the ended kinda made it feel like its a pushover getting back in an abusive relationship and less of someone trying to make it work after a bad mental health episode from their spouse.

Can someone play the devil's advocate for me about the side couple? Promise I won't fight. I just want to put the thought into proper, objective words. I know they need therapy, going back is bad blah blah that's what we all agree on. The author had treated topics maturely so far, and I applaud the author for writing a proper fucked up character other than "oh haha look at me im so fucked up i wont let u get away i have a knife i can threaten u to stay by my side" i understand Xiao Ke's character now BUT why did they make Gao Jin go back?
Wouldn't that go against the author's consistent ideals in the main couple story about a healthy relationship? Wouldn't Gao Jin coming back just reinforce Xiao Ke's unstable personality? Was it really just Gao Jin wanting Xiao Ke anyways even after all the red (which are real crimes bruv) flags? Him figuring out how Xiao Ke's mind works so he can now rest assured in a lion's den? Do they actually belong together? Have I just read their conclusion wrong and it was actually the most proper, most optimistic ending the author could give to the two of them? Am I trying to dig too deep and it's all really just Gao Jin believing Xiao Ke's "just a child" who just turned 18 and it's not the end for him and somehow Gao Jin still wants to go back to.. idk still give him a chance? (considering Gao Jin never called the police on him and all, yet never said he'd forgiven him)
there's no use threatening Xiao Ke or beating the shit out of him if we were to transmigrate to their world because i know he'll just stay the same (unless it's Gao Jin who does it ig).
Is it really just "stockholm syndrome" as one commenter had said??